1990 F150 5.0 4X4 starts then dies
 

Just bought this truck and I inherited this problem. It will turn over, it will start (sorta) and then dies. If you pump the pedal, you can keep it running, but very badly. I have verified fuel and pressure to the rail and I have spark. New TPS, fuel filter, fuel pressure regulator, dist cap and rotor. If I turn the key and let the fuel pump prime a few times it acts like it wants to run but after a few revs of running it dies.
Any help would be very appreciated...as I am not having fun.
Bob

First thing you need to do is pull the engine trouble codes and post them. Knid of sounds like it may be the idle air control valve is part of the problem, but if you pull the codes it will help greatly in determining the problem

Matt

Matt, the codes were 22 63 & 47. At the time, I had the TPS off of the truck and I assume that was the reason for the 63 code. I installed a new one with no results on the issue. Will the MAP sensor cause those symptons?

Yes I beleive it will, you also have an O2 sensor codeaccording to the chart I looked at, so the computer is thoroughly confused by the bad readings of the MAP and O2

matt

Well, I'm going to cross my greasy fingers and throw a MAP sensor and 02 sensor at it and hope it will run tomorrow. I appreciate the fast reply Matt and I'll post the results.
Bob

Pull the codes again before you buy the parts and make sure they are consistant since you changes the TPS. O2 sensors are relatively cheap and it can't hurt to put a known good one on, same with the MAp

Matt

Will do and thanks again.
Bob

That was it. The MAP sensor was bad. I also installed an 02 sensor and my codes are clear. Matt, thank you very much for the help and direction.
Bob